The Broadcast Multicast Service technology may be used to enable multiple User Equipments (UEs) to receive service data simultaneously within the range of a service coverage region. Compared with a traditional mobile communication technology in a point-to-point mode, the Broadcast Multicast Service may improve the utilities of network and spectrum resources significantly due to its provision of communication contents for multiple UEs in the service coverage range. In recent years, a technology of providing a wireless Broadcast Multicast Service using a mobile communication system develops fast, and is increasingly merged with a traditional digital audio broadcast technology, a traditional digital video broadcast technology, etc. Currently, the Multimedia Broadcast Multicast Service (MBMS) has been introduced into the 3rd generation mobile communication system defined by the 3rd Generation Partnership Project (3GPP). The MBMS refers to a point-to-multipoint service in which data is sent from one data source to multiple UEs, enabling sharing of core network resources and access network resources, particularly air interface resources. The MBMS defined by the 3GPP may implement high-speed multicast and broadcast of a multimedia service, such as the transmission of a TV service to a mobile UE.
To implement the transmission of multimedia data at a higher speed and a higher quality of service, the existing MBMS technologies are further improved in the 3GPP Long Term Evolution (LTE) plan, and an evolved MBMS (eMBMS) is proposed. FIG. 1 shows the architecture of the eMBMS, in which an RNC node is removed, and a Radio Resource Controller (RRC) and/or a Radio Link Controller (RLC) and/or a Media Access Controller (MAC) are implemented in an evolved NodeB (eNodeB). Evolved Pocket Cores (EPCs) are used to implement functions of mobility control, service bearer management, etc.
In view of the fact that a path loss and fading occurring in the transmission of a wireless signal may cause a service coverage blind spot and signal reception quality degradation in a coverage region of a wireless base station, especially at the edge of a cell, the concept of Single Frequency Network (SFN) has been proposed, in the development of the Broadcast Multicast Service technology. In the SFN, it is proposed that the same wireless interface signal is transmitted by multiple base stations, and when a UE receives the same signal from the multiple base stations, which are equivalent to multipath propagation signals from the same signal source, the macro diversity overlap coverage by the multiple base stations may be achieved due to independencies of the propagation signals from various paths, and the coverage degree and reception quality of the Broadcast Multicast Service may be significantly improved if a suitable signal processing means is selected.
A method for determining an SFN area in the prior art includes assigning the size of the SFN area based on Broadcast Multicast Service planning. After a certain time period of operation, the size of the SFN area may be reassigned when the Broadcast Multicast Service region is required to be adjusted. In such a method, the SFN area is constant between two assignment of the SFN area size, and the method is static.
However, in the practical wireless network environment, the distribution of UEs subscribing for a particular Broadcast Multicast Service may vary dynamically, and thus the UEs may be present at the edges of some SFN area cells, and cannot make full use of the SFN area because such edges are not covered by the macro diversity, resulting in a degraded reception quality.